Generator of cool working gases

ABSTRACT

Hot pressure gases are generated by burning a solid fuel grain. A portion of the gases are used to pressure feed a liquid from its storage chamber into a mixing zone. The remainder of the hot gases are directed into the mixing zone for mixing with the liquid. The hot gases provide the heat of vaporization for, and cause the vaporization of, the liquid. The gas generator comprises a one-piece housing of composite welded construction, defining liquid storage, breech and mixing chambers. A control cartridge containing burst discs, flow control orifices and seals is inserted into the housing through the outlet passageway. A solid fuel cartridge is inserted into the breech through an opening at the opposite end of the housing.

United States Patent Galbraith et al. Feb. 8, l 972 [54] GENERATOR OFCOOL WORKING 3,431,743 3/1969 Green ..62/52 GASES Primary Examiner-MeyerPerlin [72] Inventors: Lyle D. Galbraith, Redmond; William F. AssistantExaminer Ronald capossela v Thorn, Mercer Island, both of Wash. Atmmey(;raybea], Co|e & Barnard [73] Assignee: lvlvogzslijevt ResearchCorporation, Redmond, ABS CT [22] Filed: Man 27 1970 Hot pressure gasesare generated by burning a solid fuel grain. A portion of the gases areused to pressure feed a liquid from [21] Appl. N -I 2 ,1 its storagechamber into a mixing zone. The remainder of the hot gases are directedinto the mixing zone for mixing with the liquid. The hot gases providethe heat of vaporization for, and (5| ..62/52,F cause the vaporizationof, the liquid. The g generator 58] i I52 prises a one-piece housing ofcomposite welded construction,

' 60/39 defining liquid storage, breech and mixing chambers. A controlcartridge containing burst discs, flow control orifices and seals isinserted into the housing through the outlet [56] References cuedpassageway. A solid fuel cartridge is inserted into the breech UNITEDSTATES PATENTS through an opening at the opposite end of the housing.3,431,742 3/1969 Green ..62/52 26 Claims, 7 Drawing Figures PATENTEDFEB81972 3.640.083

sum 2 or 3 my, M 6, WW1

A r roPA/yf BACKGROUND OF THE INVENTION 1. Field ofthe Invention Thepresent invention relates primarily to the generation of a relativelylow-temperature working fluid, and in particular to a construction ofthe equipment or hardware for handling and combining the substanceswhich produce the working fluid.

Herein the expressions relatively low temperature working fluid, coolworking gases" and cool gas generator" are used to respectively describegases which are relatively cool when compared to undiluted combustiongases or reaction products, and generators of same.

2. Description of the Prior Art Known gas or gas-included fluidgenerators which involve mixing combustion products and a coolant aredisclosed by Goddard U.S. Pat. No. 2,522,113; Scholz U.S. Pat. No.2,530,633; Maurice U.S. Pat. No. 2,779,281; Volk, Jr. U.S. Pat. No.2,994,194, Barakauskas U.S. Pat. No. 3,182,554; and Barakauskas U.S.Pat. No. 3,298,278, and also by Hebenstreit U.S. Pat. No. 3,117,424;Hebenstreit et al. U.S. Pat. No. 3,122,181; Hebenstreit U.S. Pat. No.3,143,445; Wismar U.S. Pat. No. 3,163,014; Hebenstriet U.S. Pat. No.3,180,373; Hebenstreit U.S. Pat. No. 3,232,481 and Wismar U.S. Pat. No.3,269,310.

Each of the latter seven patents involves a system wherein combustionproducts and a liquefied gas are mixed together in the storage chamberfor the liquefied gas, and the resulting mixture, which is gaseous, isthen released or withdrawn from such storage chamber.

Wismar U.S. Pat. No. 3,163,014 discloses a process comprising:generating hot combustion gases and initially directing all of suchgases into a chamber containing liquefied carbon dioxide. Such chamberis initially closed by a blowout element. When the pressure in suchchamber exceeds the burst pressure of the blowout element, such elementis ruptured, and the outlet is opened. The remaining combustion gasesthen serve to aspirate the mixture of gases from the carbon dioxidestorage chamber.

Hebenstreit et al. U.S. Pat. No. 3,122,181 discloses entraining ambientair in a working fluid constituting a mixture of combustion gases andcarbon dioxide, and then introducing the mixture into an inflatabledevice.

Barakauskas U.S. Pat. Nos. 3,182,554 3,298,278 disclose adding water tocombustion gases and then directing the resulting gas-water-steammixture into a space below a missile for exerting a launching force onthe missile.

The present invention relates to a particular gas generator capable ofperforming the methods disclosed in the Charles J. Green U.S. Pat. Nos.3,431,742 and 3,431,743, both granted on Mar. 11, 1969, and bothentitled Generation of Cool Working Fluids.

SUMMARY OF THE INVENTION Briefly, the gas generators of this inventioneach comprises a housing of welded composite form, includingconcentrically related inner and outer housing parts. The outer housingpart includes a cylindrical body. The inner housing part includes aflanged tubular outlet member and a tubular body member. In one form ofthe invention a one-piece inlet ring member is welded to the inlet endsof the two body members. In another form one piece of a two-piece inletring is welded to the inlet end of the outer body member and the otherpiece is welded to the inlet end of the inner body member. In both formsduring fabrication of the housing the inner housing part is insertedinto the outer housing part and the two housing parts are weldedtogether at the two ends of the generator.

The inlet ring member is internally threaded to receive the threads of aretainer ring restraining an end closure which carries a firing assemblyfor the fuel grain. The fuel grain is inserted into the gas generatorthrough an inlet opening in the inlet ring member and then the endclosure member and retainer ring are installed. A control orifice andburst disc insert is inserted into, and after use is removed from-theassembly via an outlet passageway provided in the outlet member of theinner housing part.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of acool gas generator embodying features of the present invention, shown ina leaning attitude typical of one it might occupy in some aircraftescape slide inflation systems;

FIG. 2 is a longitudinal sectional view of the cool gas generator ofFIG. 1, prior to activation, with a closure plug thereof shown spacedoutwardly from its installed position;

FIG. 3 is a view like FIG. 2, but showing the generator in an activecondition;

FIG. 4 is a cross-sectional view taken substantially along line 4-4 ofFIG. 3;

FIG. 5 is an exploded view of various casing parts which make up the gasgenerator of FIGS. 1-4, with the liquid pickup tube, its connector, thegas deflector, and the retainer ring omitted;

FIG. 6 is an end elevational view at the inlet end of the assembledcasing members, with the inlet and closure member removed and the outletend details omitted; and

FIG. 7 is an exploded view of the housing parts only of a modified formof gas generator.

DETAILED DESCRIPTION Referring more specifically to the figures of thedrawing, the cool gas generator of FIGS. 1-6 is shown to comprise anouter enclosure or casing 10 of elongated tubular form. Located insideof enclosure 10 is a smaller inner tubular enclosure 12. An annularspace 14 exists between the respective annular sidewall means of the twoenclosures l0, 12. This space 14 constitutes a storage space for thevaporizable liquid L.

The inner enclosure 12 is axially divided into a breech or hot gasgenerator chamber 16 and an outlet passageway 18. Chamber 16 is shown tocontain a solid fuel grain 20. A percussion-type firing mechanism 22 isillustrated by way of typical example only. Also by way of typical andtherefore nonlimiting example, the fuel grain 20 may be constructedaccording to any of the designs of fuel grains disclosed by theaforementioned U.S. Pat. No. 3,431,742.

The upstream end portion of the outlet passageway 18 includes a grainsupport 21 formed to include a-plurality of gas openings 19. Some of thehot gases flow through these openings 19 into the annular space 23 whichsurrounds grain 20, for substantially equalizing the pressure on thegrain casing. This makes it possible to use a thin casing materialaround the grain 20.

A control orifice insert 24 is supported within the outlet passageway18. Insert 24 is shown to include an axial passageway 26 through whichmost of the hot gases flow. Insert 24 also includes an enlarged inletcavity 28. A second hot gas passageway extends from the inlet cavity 28into the liquid storage space 14. This "passageway comprises one or moregenerally radial ports 30 formed in the insert 24, a girth channel orgroove 32 formed in the insert in the vicinity of where the port(s) 30breaks the periphery of the insert 24, and one or more radial ports 34formed in the wall of the outlet passageway 18.

A shoulder 36 (FIGS. 2, 3 and 5) serves as a spacing stop for the insert24. When the forward end of the insert 24 is against shoulder 36, andthe snapring 37 (FIGS. 2 and 3) is placed within girth groove 39 (FIG.5), groove 32 is properly aligned with the port(s) 34. The use of agirth groove 32 makes it possible for the port(s) 30 to always be incommunication with the port(s) 34 (via groove 32) regardless of theangular position of the insert 24 in its receiving chamber.

A second girth groove or channel 38 is formed in the insert 24,downstream of groove 32. When the front end of the insert 24 is againstthe stop 36 this channel 38 is in communication with one or more radialports 41 formed in the sidewall of outlet passageway 18. One or moreports 40 in insert 24 communicate the channel 38 with an enlarged outletcavity 42 in the insert 24.

The insert 24 includes a plurality of axially spaced girth grooves forreceiving sealing O-rings. The first O-ring 44 (FIGS. 2 and 3) isprovided in insert 24. upstream of groove 32. The second O-ring 46 islocated between grooves 32 and 38. The third O-ring 48 is locateddownstream of groove 38 and may be at larger diameter-than O-rings 44,46.

The'insert 24 is constructed for receiving and retaining a pair of burstdiscs 50, 52. The upstream burst disc 50 is located upstream of theinlets for port(s) 30 and passageway 26. The second burst disc 52 islocated downstream of the outlets from port(s) 40 and passageway 26.

In a typical escape slide inflation installation such as shown by FIG. 1the gas generator may occupy an inclining attitude of X degrees (shownby way of example to be about fifteen degrees (15") to horizontal). Thegas generator may occupy such an attitude withina compartment preparedfor it within the door for the opening in the aircraft with which theescape slide to be inflated is associated. Of course, it is to beunderstood that the gas generator has general utility and in otheraircraft or nonaircraft installations may occupy an entirely differentattitude.

When the gas generator is in the sloping attitude pictured, the lowestportion 54 of the liquid storage space 14 is near the inletend of thegas generator. A liquid pickup tube 56 extends from this region 54 up toa point of connection with thewall means for passageway 18, at alocation enveloping the port(s) 41. Of course, in other installationsinvolving a different attitude of the gas generator the inlet for thepickup tube 56 is located in the region of the low point for suchinstallation.

Preferably, a gas deflector ismounted on outlet passageway 18 radiallyoutwardly from the port(s) 34. In FIGS. 24 this deflector is shown inthe form of a sheet material hood 58 having an end-wall 60 aligned withthe port 34 and having sidewall openings 62.

In operation, the fuel grain 20 is initiated by a pulling-on or other(e.g., electrical control) release of the firing pin, to activate thefiring mechanism 22. Burst discs 50, 52 break (almost simultaneously)when the pressure on them exceeds a predetermined value. A first portionof hot gases flows through the ports 30, 34 and into the liquid storagechamber 14. The hot gases entering the storage chamber 14 pressurize theliquid L therein and force feed it through the pickup tube 56 towardsthe annular manifold 38. The pressurized liquid L flows from manifold 38through the ports 40 and into mixing contact with the hot gases issuingfrom passageway 26. The hot gases and liquid meet and mix together inoutlet cavity 42. The outlet cavity 42 is at least the start of a mixingchamber or zone. In some installations some mixing may continue in thepassageway downstream of cavity 42. The hot gases supply the latent heatof vaporization for the liquid, causing its vaporization, attended by asignificant cooling of the hot gases. The relatively cool gaseousworking fluid that is formed then flows from the outlet passageway 18through a conduit 64 to a utilization device, e.g., the inlet of a gasconfining type inflatable.

By way of nonlimitive example, the liquid may be a liquefied fluorinatedhydrocarbon type refrigerant, liquefied carbon dioxide, liquefied air,liquefied ammonia, a mixture of liquefied ammonia and water, i.e.,aqueous ammonia, water alone, or a mixture of these or other suchmaterials blended to produce gaseous mixtures of various desiredcompositions and properties.

Referring now to FIGS. and 6, relating to a preferred construction ofthe gas generator housing and fluid control parts. The outer housing isshown to comprise a cylindrical shell 66 and a specially formed (e.g.,forged or east) end piece 68. The piece 68 is welded to one end ofcylinder 66 at weld line 70, The opposite end of cylinder 66 is eitherdrawn into the shape shown, or the generally hemispherical section 72 isseparately formed and is then welded to the cylinder 66 (at location w).The inner housing assembly 16 comprises a cylindrical intennediateportion 74, a specially constructed (e.g., forged or cast) inlet endmember 76 and a specially fabricated (e.g., forged, machined or cast)opposite end member 80 which defines the outlet passageway, includingthe cavity 82 for the insert 24. The generally ellipsoidal portion 84 ofcylinder 74 may be a draw-formed part of cylinder 74, or may be aseparately constructed member which is later welded to the cylinder 74(at location w), or may be included as a part of member 80.

Member 80 includes a generally radial-contoured flange 86. In theillustrated embodiment member 80 is welded at 88 to the section 84 ofcylinder 74.

In assembly, the downstream end of the inner housing 16 is insertedthrough the inlet opening ,90 of outer housing 10. The inner housing 16is then moved completely into the outer housing 10 until the edgesurface 92 of flange 86 is adjacent the edge surface 94 of section 72,and the edge surface 96 of member 76 is adjacent the edge surface 98 ofmember 68. Then the two housings are welded together where the surfaces92, 94 meet and where the surfaces 96, 98 meet. The gap between surfaces96, 98 is completely filled by weld 100. Then, fill and liquid levelindicator openings 102, 104 (FIG. 6) are drilled through the welded areaand are tapped for receiv ing a threaded closure fitting or plugtherein. The closure plug 103 for opening 102 is shown in FIGS. 2 and 3.The firing mechanism 22 is carried by a cap 101 insertable in throughopening 108, and retained in place by retainer ring means 105, as shownin FIGS. 2 and 3. The cap 101 also includes a threaded opening forreceiving a safety burst disc fitting 107.

FIG. 7 shows a slightly modified form of the generator. In thisembodiment of the invention a one-piece end ring is used. Duringassembly the ring 110 is welded at 112 to the inlet end of member 74.With member 80 attached (by welding) the inner assembly is inserted intomember 66. Then ring 110 is welded at 114 to the inlet end of member 66and member 66 is welded at 94 to the flange 86 at 92, but notnecessarily in this order.

Ring member 110 is threaded at 118 to receive the retainer ring means105, as shown in FIGS. 2 and 3.

In both embodiments the inner and outer housing assemblies l0, 16 arepermanently joined so that the resulting housing structure is ofone-piece composite form.

Liquid pickup tube 56 is secured at its outlet end to the member 80. Aconnector 57 is used to secure the opposite end of tube 56 to a portionof wall 16. This connector 57 has a generally U-shaped central portionwhich partially surrounds tube 56 and straplike end portions which aresecured to the wall 16.

Following a use of a generator its insert 24 is removed from thegenerator via the outlet opening 106, and is replaced by a new insertthrough the same opening 106. Similarly, the spent solid fuel cartridge20 is removed from the breech chamber 16 via the opening 108 (FIG. 5) inmember 76, or opening 116 (FIG. 7) in member 110, and a new cartridge 20is replaced through the same opening.

Another important advantage of the construction of this gas generator isthat a family of several sizes of gas generators can be easily builtwithout having to fabricate an entirely new set of gas generator parts.According to the invention, for a given family of sizes it is onlynecessary to vary the lengths of the cylinders 66, 74 and the length ofthe fuel grain 20. The other parts of the gas generator are standard andmay be used with any size generator of the family. In some installationsit may be desirable to vary the size of the ports in insert 24 from onesize to the next, but this is an easy and inexpensive modification.Additional ranges of sizes-may be similarly provided in a larger orsmaller diameter generator by similar length variations.

As a safety feature, the insert 24 is provided with an enlarged diameterouter end portion. If the insert 24 is not seated tight against surface36 and the snapring 37 is not properly within groove 39, the vaporpressure of the stored liquid will exert a force on surface 120, causingejection of insert 24. Thus, the gas generator will not let the personloading it forget to install, or to improperly install, snapring 37.

The restricted nature of passageway 26 is a very important feature ofthe invention. It causes a pressure drop which makes flow of the liquidpossible. Owing to the presence of this restriction 26 the pressure inregion 42 is less than in chamber 14. Thus, the gas pressure on theliquid in chamber 14 force feed the liquid into the zone 42.

As heretofore stated, the gas generator has general utility. Examples ofuses in addition to escape slide inflation include: for turbineoperation, for undersea flotation bag inflation, for flotation systemsgenerally, and for controlled temperature hot gas supply systems.

These and other variations, modifications, adaptations, features andcharacteristics of cool gas generators according to the presentinvention will be apparent to those skilled in the art to which suchinvention is addressed, within the scope of the following claims.

What is claimed is:

l. A cool gas generator, comprising:

outer housing means;

smaller diameter inner housing means inside said outer housing means;

with a storage space for a liquid existing about the inner housingmeans, between it and the outer housing means, and a vaporizable liquidin said space;

said inner housing means comprising tubular wall means defining a hotgas generation chamber and a communicating tubular outlet sectionextending from said chamber to an outlet opening in said outer housingmeans; generation means in said hot gas generator chamber for generatinghot gases therein, for release therefrom into said outlet section;

said inner housing means also including a hot gas passageway leadingfrom the interior thereof into said storage space, for delivering afirst portion of the hot gases into said space, and a liquid passagewaydownstream of said hot gas passageway, leading from said space into saidoutlet section, and conduit means leading from said outlet section to autilization station; and

the improvement comprising:

the tubular wall means defining the outlet section has first and secondports therein, one of which constitutes a portion of said hot gaspassageway and the other of which constitutes a portion of said liquidpassageway; and

an elongated, replaceable control insert snugly received inside saidoutlet section, said insert having inlet and outlet portions, andelongated, generally axial, small diameter passageway therein, extendingfrom said inlet portion to said outlet portion, through which a secondportion of the hot gases flow, a first side port extending from saidinlet portion to the hot gas passageway port in said tubular wall means,in parallel flow relationship to said generally axial passageway, asecond side port extending from said outlet portion to the liquidpassageway port in said tubular wall means, a first pressure-releaseableclosure member spanning across and initially closing the inlet endportion at a location upstream of the entrances of both said first sideport and said generally axial passageway, and a secondpressurereleaseable closure member spanning across and initially closingthe outlet portion, at a location downstream of the outlets of both saidsecond side port and said generally axial passageway.

2. A cool gas generator according to claim 1, wherein said insert isaccessible from the outlet opening in the outer housing, so that it canbe removed and replaced by a new insert through said outlet opening.

3. A cool gas generator according to claim 1, wherein said insertincludes a peripheral groove on each side of each side port and anO-ring in each groove, for sealing between the insert and the tubularwall means of the outlet section.

4. A cool gas generator according to claim 1, further includingdeflector means secured to the tubular wall means of the outlet section,for turning the hot gases issuing from said first port and directingthem substantially axially.

5. A cool gas generator according to claim 1, wherein said insertincludes a girth channel surrounding its periphery where each said sideport meets the periphery, so that the side ports of the insert arealways in. communication with the ports in the tubular wall of theoutlet section regardless of the angular relationship of the insertports to the ports in the sidewall means.

6. A cool gas generator according to claim 1, wherein the inlet andoutlet portions of said insert are larger in diameter than saidgenerally axial passageway through the insert, said first side port hasits entrance in said inlet portion, upstream of the entrance to saidgenerally axial passageway, and the second side port discharges intosaid outlet portion, downstream of the discharge end of said generallyaxial passageway.

7. A cool gas generator, comprising:

an elongated, generally cylindrical, outer sidewall member having firstand second ends; a an elongated, generally cylindrical, inner sidewallmember having first and second ends, said member being both shorter andsmaller in diameter than said outer member and being located inside saidouter member;

ringwall means connecting together the first ends of said sidewallmembers and forming a radial wall between said first ends, said ringwallmeans including an open center for receiving a gas generator graincartridge assembly insertable through said center into the innersidewall member;

an outlet member having a first end connected to the second end of saidinner sidewall member, said outlet member extending from said second endof the inner sidewall member through an opening in the second end of theouter side member, and having an outlet opening at its second end, withsaid outer sidewall member meeting said outlet member in the vicinity ofsaid outer wall opening to form an end closure for the annular spacewhich surrounds said inner sidewall member and the portion of the outletmember which is housed therein, said outlet member including sidewallmeans forming an axial chamber therein, first and second sidewallopenings in said sidewall means extending between said chamber and saidannular space; and

an elongated, replaceable control insert snugly received inside saidchamber, said insert having inlet and outlet portions, an elongated,generally axial, small diameter passageway therein, extending from saidinlet portion to said outlet portion, a first side port extending fromsaidv inlet portion to the first sidewall opening and a second side portextending from said outlet portion to said second sidewall port.

8. A cool gas generator according to claim 7, wherein said insert isaccessible from the outlet opening in said outlet member, so that it canbe removed and replaced by a new insert through said outlet opening.

9. A cool gas generator according to claim 7, wherein the opening at thesecond end of the outer sidewall member is larger in diameter than thecontrol insert containing portion of said outlet member and said outletmember includes a radial flange which projects outwardly to the rim ofsaid opening, and is connected thereto.

10. A cool gas generator according to claim 7, wherein said insertincludes a peripheral groove on each side of each side port and anO-ring in each groove, for sealing between the insert and the tubularwall means of the outlet section.

11. A cool gas generator according to claim 7, further includingdeflector means secured to the tubular wall means of the outlet section,for turning the hot gases issuing from said first port and directingthem substantially axially.

12. A cool gas generator according to claim 7, wherein said insertincludes a girth channel surrounding its periphery where each said sideport meets the periphery, so that the sideports of the insert are alwaysin communication with the ports in the tubular wall of the outletsection regardless of the angular relationship of the insert ports tothe ports in the sidewall means,

13. A cool gas generator according to claim 7, wherein the inlet andoutlet portions of said insert are larger in diameter than saidgenerally axial passageway through the insert, said first side portincluding its entrance in said inlet portion, upstream of the entranceto said generally axial passageway, and the second side port dischargesinto said outlet portion, downstream of the discharge end of saidgenerally axial passageway.

14. A cool gas generator comprising:

generally concentric inner and outer housing means defining an annularstorage space between them which is closed at both of its ends, saidinner housing means including a combustion chamber, a control insertchamber, a mixing zone, and an outlet in series, said inner casing alsoincluding an access opening at the combustion chamber end therein,through which a solid fuel grain may be inserted into the combustionchamber, and a removable closure for said opening, said closure carryinginitiator means for said grain, and a control insert insertable into andremovable from its chamber through the outlet of said inner housingmeans, said control insert comprising a first metering passageway forcombustion gases leading to the mixing zone, a second combustion gasespassageway leading into the storage space, for supplying pressurizinggases into said space, and an outlet passageway leading from saidstorage space into the mixing zone.

15. A cool gas generator according to claim 14, wherein said insertincludes a peripheral groove on each side of each side port and anO-ring in each groove, for sealingbetween the insert and the tubularwall means of the outlet section.

16. A cool gas generator according to claim 14, further includingdeflector means secured to the tubular wall means of the outlet section,for turning the hot gases issuing from said first port and directingthem substantially axially.

17. A cool gas generator according to claim 14, wherein said insertincludes a girth channel surrounding its periphery where each said sideport meets the periphery, so that the side ports of the insert arealways in communication with the ports in the tubular wall of the outletsection regardless of the angular relationship of the insert ports tothe ports in the sidewall means 18. A cool gas generator according toclaim 14, wherein the inlet and outlet portions of said insert arelarger in diameter than said generally axial passageway through theinsert, said first side port has its entrance in said inlet portion,upstream of the entrance to said generally axial passageway, and thesecond side port discharges into said outlet portion, downstream of thedischarge end of said generally axial passageway.

19. A cool gas generator, comprising:

a one-piece housing formed from integrally joined inner and outertubular wall means defining a liquid storage space between them;

said inner wall means defining communicating breech, control insert andmixing chambers;

said housing being open at one end of the inner wall means for insertionof a fuel cartridge through such end into the breech chamber;

said housing being open in the vicinity of the mixing chamber forinsertion of a control insert through such opening and the mixingchamber into the control insert chamber;

said inner wall means having openings therein in the vicinity of thecontrol insert chamber, for communicating the interior of the controlinsert chamber with the liquid storage space; and a control insert sizedto snugly fit mside said control insert chamber and including a firstmetering orifice leading through it, for communicating the breechchamber with the mixing chamber, a second metering orifice forcommunicating the breech chamber with the interior of the liquid storagespace, via a said opening in the control insert chamber portion of theinner wall means, and a third metering orifice for communicating theinterior of the liquid storage space with the mixing chamber, via a saidopening in the control insert chamber portion of the inner wall means.

20. A cool gas generator according to claim 19, wherein said insertincludes a peripheral groove on each side of each side port and anO-ring in each groove, for sealing between the insert and the tubularwall means of the outlet section.

21. A cool gas generator according to claim 19, further includingdeflector means secured to the tubular wall means of the outlet section,for turning the hot gases issuing from said first port and directingthem substantially axially.

22.. A cool gas generator according to claim 19, wherein said insertincludes a girth channel surrounding its periphery where each said sideport meets the periphery so that the side ports of the insert are alwaysin communication with the ports in the tubular wall of the outletsection regardless of the angular relationship of the insert parts tothe ports in the sidewall means.

23. A cool gas generator according to claim 19, wherein the inlet andoutlet portions of said insert are larger in diameter than saidgenerally axial passageway through the insert, said first side port hasits entrance in said inlet portion, upstream of the entrance to saidgenerally axial passageway, and the second side port discharges intosaid outlet portion, downstream of the discharge end of said generallyaxial passageway.

24. A cool gas generator according to claim I, wherein said second andthird metering orifices are side ports in said insert, and said insertincludes a girth channel surrounding its periphery where each said sideport meets the periphery, so that the side ports of the insert arealways in communication with the ports in the tubular wall of the outletsection regardless of the angular relationship of the insert ports tothe ports in the sidewall means.

25. A cool gas generator according to claim 1, wherein the insertincludes relatively enlarged inlet and outlet portions which areinterconnected by the first orifice through the insert which orificefunctions as a pressure-reducing restriction, said second orifice sideport has its entrance in said inlet portion,

upstream of the entrance to the first orifice, and the third orificeside port discharges into said outlet portion, downstream of thedischarge end of said first orifice.

26. A cool gas generator according to claim 19, wherein said controlinsert has an enlarged-diameter outlet end portion including surfaces incommunication with the stored liquid pressure, and retainer means forholding the insert in place, with the stored liquid pressure acting onsaid surface of said enlarged diameter outlet end serving to force theinsert out of the outlet section if it is not properly retained by saidretainer means.

1. A cool gas generator, comprising: outer housing means; smallerdiameter inner housing means inside said outer housing means; with astorage space for a liquid existing about the inner housing means,between it and the outer housing means, and a vaporizable liquid in saidspace; said inner housing means comprising tubular wall means defining ahot gas generation chamber and a communicating tubular outlet sectionextending from said chamber to an outlet opening in said outer housingmeans; means in said hot gas generation chamber for generating hot gasestherein, for release therefrom into said outlet section; said innerhousing means also including a hot gas passageway leading from theinterior thereof into said storage space, for delivering a first portionof the hot gases into said space, and a liquid passageway downstream ofsaid hot gas passageway, leading from said space into said outletsection, and conduit means leading from said outlet section to autilization station; and the improvement comprising: the tubular wallmeans defining the outlet section has first and second ports therein,one of whiCh constitutes a portion of said hot gas passageway and theother of which constitutes a portion of said liquid passageway; and anelongated, replaceable control insert snugly received inside said outletsection, said insert having inlet and outlet portions, an elongated,generally axial, small diameter passageway therein, extending from saidinlet portion to said outlet portion, through which a second portion ofthe hot gases flow, a first side port extending from said inlet portionto the hot gas passageway port in said tubular wall means, in parallelflow relationship to said generally axial passageway, a second side portextending from said outlet portion to the liquid passageway port in saidtubular wall means, a first pressure-releaseable closure member spanningacross and initially closing the inlet end portion at a locationupstream of the entrances of both said first side port and saidgenerally axial passageway, and a second pressure-releaseable closuremember spanning across and initially closing the outlet portion, at alocation downstream of the outlets of both said second side port andsaid generally axial passageway.
 2. A cool gas generator according toclaim 1, wherein said insert is accessible from the outlet opening inthe outer housing, so that it can be removed and replaced by a newinsert through said outlet opening.
 3. A cool gas generator according toclaim 1, wherein said insert includes a peripheral groove on each sideof each side port and an O-ring in each groove, for sealing between theinsert and the tubular wall means of the outlet section.
 4. A cool gasgenerator according to claim 1, further including deflector meanssecured to the tubular wall means of the outlet section, for turning thehot gases issuing from said first port and directing them substantiallyaxially.
 5. A cool gas generator according to claim 1, wherein saidinsert includes a girth channel surrounding its periphery where eachside side port meets the periphery, so that the side ports of the insertare always in communication with the ports in the tubular wall of theoutlet section regardless of the angular relationship of the insertports to the ports in the sidewall means.
 6. A cool gas generatoraccording to claim 1, wherein the inlet and outlet portions of saidinsert are larger in diameter than said generally axial passagewaythrough the insert, said first side port has its entrance in said inletportion, upstream of the entrance to said generally axial passageway,and the second side port discharges into said outlet portion, downstreamof the discharge end of said generally axial passageway.
 7. A cool gasgenerator, comprising: an elongated, generally cylindrical, outersidewall member having first and second ends; an elongated, generallycylindrical, inner sidewall member having first and second ends, saidmember being both shorter and smaller in diameter than said outer memberand being located inside said outer member; ringwall means connectingtogether the first ends of said sidewall members and forming a radialwall between said first ends, said ringwall means including an opencenter for receiving a gas generator grain cartridge assembly insertablethrough said center into the inner sidewall member; an outlet memberhaving a first end connected to the second end of said inner sidewallmember, said outlet member extending from said second end of the innersidewall member through an opening in the second end of the outer sidemember, and having an outlet opening at its second end, with said outersidewall member meeting said outlet member in the vicinity of said outerwall opening to form an end closure for the annular space whichsurrounds said inner sidewall member and the portion of the outletmember which is housed therein, said outlet member including sidewallmeans forming an axial chamber therein, first and second sidewallopenings in said sidewall means extending between said chamber and saidannular space; and an elongated, replaceable control insert snuglyreceived inside said chamber, said insert having inlet and outletportions, an elongated, generally axial, small diameter passagewaytherein, extending from said inlet portion to said outlet portion, afirst side port extending from said inlet portion to the first sidewallopening and a second side port extending from said outlet portion tosaid second sidewall port.
 8. A cool gas generator according to claim 7,wherein said insert is accessible from the outlet opening in said outletmember, so that it can be removed and replaced by a new insert throughsaid outlet opening.
 9. A cool gas generator according to claim 7,wherein the opening at the second end of the outer sidewall member islarger in diameter than the control insert containing portion of saidoutlet member and said outlet member includes a radial flange whichprojects outwardly to the rim of said opening, and is connected thereto.10. A cool gas generator according to claim 7, wherein said insertincludes a peripheral groove on each side of each side port and anO-ring in each groove, for sealing between the insert and the tubularwall means of the outlet section.
 11. A cool gas generator according toclaim 7, further including deflector means secured to the tubular wallmeans of the outlet section, for turning the hot gases issuing from saidfirst port and directing them substantially axially.
 12. A cool gasgenerator according to claim 7, wherein said insert includes a girthchannel surrounding its periphery where each said side port meets theperiphery, so that the side ports of the insert are always incommunication with the ports in the tubular wall of the outlet sectionregardless of the angular relationship of the insert ports to the portsin the sidewall means.
 13. A cool gas generator according to claim 7,wherein the inlet and outlet portions of said insert are larger indiameter than said generally axial passageway through the insert, saidfirst side port has its entrance in said inlet portion, upstream of theentrance to said generally axial passageway, and the second side portdischarges into said outlet portion, downstream of the discharge end ofsaid generally axial passageway.
 14. A cool gas generator comprising:generally concentric inner and outer housing means defining an annularstorage space between them which is closed at both of its ends, saidinner housing means including a combustion chamber, a control insertchamber, a mixing zone, and an outlet in series, said inner casing alsoincluding an access opening at the combustion chamber end therein,through which a solid fuel grain may be inserted into the combustionchamber, and a removable closure for said opening, said closure carryinginitiator means for said grain, and a control insert insertable into andremovable from its chamber through the outlet of said inner housingmeans, said control insert comprising a first metering passageway forcombustion gases leading to the mixing zone, a second combustion gasespassageway leading into the storage space, for supplying pressurizinggases into said space, and an outlet passageway leading from saidstorage space into the mixing zone.
 15. A cool gas generator accordingto claim 14, wherein said insert includes a peripheral groove on eachside of each side port and an O-ring in each groove, for sealing betweenthe insert and the tubular wall means of the outlet section.
 16. A coolgas generator according to claim 14, further including deflector meanssecured to the tubular wall means of the outlet section, for turning thehot gases issuing from said first port and directing them substantiallyaxially.
 17. A cool gas generator according to claim 14, wherein saidinsert includes a girth channel surrounding its periphery where eachsaid side port meets the periphery, so that the side ports of the insertare always in communication with the ports in the tubular wall of theoutlet section regardless of the angUlar relationship of the insertports to the ports in the sidewall means
 18. A cool gas generatoraccording to claim 14, wherein the inlet and outlet portions of saidinsert are larger in diameter than said generally axial passagewaythrough the insert, said first side port has its entrance in said inletportion, upstream of the entrance to said generally axial passageway,and the second side port discharges into said outlet portion, downstreamof the discharge end of said generally axial passageway.
 19. A cool gasgenerator, comprising: a one-piece housing formed from integrally joinedinner and outer tubular wall means defining a liquid storage spacebetween them; said inner wall means defining communicating breech,control insert and mixing chambers; said housing being open at one endof the inner wall means for insertion of a fuel cartridge through suchend into the breech chamber; said housing being open in the vicinity ofthe mixing chamber for insertion of a control insert through suchopening and the mixing chamber into the control insert chamber; saidinner wall means having openings therein in the vicinity of the controlinsert chamber, for communicating the interior of the control insertchamber with the liquid storage space; and a control insert sized tosnugly fit inside said control insert chamber and including a firstmetering orifice leading through it, for communicating the breechchamber with the mixing chamber, a second metering orifice forcommunicating the breech chamber with the interior of the liquid storagespace, via a said opening in the control insert chamber portion of theinner wall means, and a third metering orifice for communicating theinterior of the liquid storage space with the mixing chamber, via a saidopening in the control insert chamber portion of the inner wall means.20. A cool gas generator according to claim 19, wherein said insertincludes a peripheral groove on each side of each side port and anO-ring in each groove, for sealing between the insert and the tubularwall means of the outlet section.
 21. A cool gas generator according toclaim 19, further including deflector means secured to the tubular wallmeans of the outlet section, for turning the hot gases issuing from saidfirst port and directing them substantially axially.
 22. A cool gasgenerator according to claim 19, wherein said insert includes a girthchannel surrounding its periphery where each said side port meets theperiphery, so that the side ports of the insert are always incommunication with the ports in the tubular wall of the outlet sectionregardless of the angular relationship of the insert ports to the portsin the sidewall means.
 23. A cool gas generator according to claim 19,wherein the inlet and outlet portions of said insert are larger indiameter than said generally axial passageway through the insert, saidfirst side port has its entrance in said inlet portion, upstream of theentrance to said generally axial passageway, and the second side portdischarges into said outlet portion, downstream of the discharge end ofsaid generally axial passageway.
 24. A cool gas generator according toclaim 1, wherein said second and third metering orifices are side portsin said insert, and said insert includes a girth channel surrounding itsperiphery where each said side port meets the periphery, so that theside ports of the insert are always in communication with the ports inthe tubular wall of the outlet section regardless of the angularrelationship of the insert ports to the ports in the sidewall means. 25.A cool gas generator according to claim 1, wherein the insert includesrelatively enlarged inlet and outlet portions which are interconnectedby the first orifice through the insert which orifice functions as apressure-reducing restriction, said second orifice side port has itsentrance in said inlet portion, upstream of the entrance to the firstorifice, and the third orifice side port discharges into Said outletportion, downstream of the discharge end of said first orifice.
 26. Acool gas generator according to claim 19, wherein said control inserthas an enlarged-diameter outlet end portion including surfaces incommunication with the stored liquid pressure, and retainer means forholding the insert in place, with the stored liquid pressure acting onsaid surface of said enlarged diameter outlet end serving to force theinsert out of the outlet section if it is not properly retained by saidretainer means.